As a method for driving an openable and closable body that opens and closes with rotation, such as a backdoor of an automobile or an outward-opening window, there is a method using an openable and closable body-opening and closing apparatus that operates to open and close the openable and closable body. In this openable and closable body-opening and closing apparatus, for example, an opening and closing operation of the openable and closable body is controlled by controlling extension and retraction of a shaft driven by a motor. This enables appropriate adjustment of an opening and closing position and/or an opening and closing speed of the openable and closable body without directly opening and closing the openable and closable body by a human. For this reason, this openable and closable body-opening and closing apparatus has high usability.
The openable and closable body-opening and closing apparatus as described above is provided with, for example, a spindle that is rotationally driven by a motor, a spindle nut that converts a rotary motion of the spindle into displacement in a rotation axis direction, and a push rod coupled to the spindle nut. In addition, this openable and closable body-opening and closing apparatus using the spindle is further provided with, for example, a guide portion that guides movement of the spindle nut in the rotation axis direction, and a cylindrical spring that assists the displacement of the spindle nut in the rotation axis direction (e.g., see Patent Literature (hereinafter, referred to as “PTL”) 1). In this openable and closable body-opening and closing apparatus, the push rod supporting the spindle nut that is displaced in the axis direction of the spindle by the motor driving causes the openable and closable body attached to a ball socket at a distal end of the push rod to perform opening and closing motion. During this operation, the cylindrical spring provided outside the guide portion for guiding the spindle nut outside the spindle nut assists the opening and closing motion of the openable and closable body, thereby making it possible to drive the openable and closable body to open and close with a relatively low driving force of the motor.